Search found 1043 matches
- 7 years ago
- Forum: Tools
- Topic: Reading zipped archive with csv2gdx
- Replies: 1
- Views: 3655
Re: Reading zipped archive with csv2gdx
Tara got some help from GAMS support but I want to share some of our findings. First of all csv2gdx processes a single CSV file to create a single GDX file with a single parameter. So there is no batch processing in csv2gdx. Here are some other considerations when processing large CSV files. Python ...
- 7 years ago
- Forum: Solvers
- Topic: cplex unable to load name
- Replies: 0
- Views: 5359
Re: cplex unable to load name
Hmmm, there can be a few reasons why the loading of the names fails. First you might have disabled the generation of names inside the GAMS code. One can do this by setting mymodel.dictfile=0; before the solve statement (https://www.gams.com/latest/docs/userguides/mccarl/model_attributes_mainly_used_...
- 7 years ago
- Forum: Modeling
- Topic: how to generate lp file without solving it
- Replies: 0
- Views: 11458
Re: how to generate lp file without solving it
Hi, I don't know what kind of debugging you want to do but usually the equation listing in the listing file is a pretty good debugging tool if you visually need to inspect your constraints: A Transportation Problem (TRNSPORT,SEQ=1) Equation Listing SOLVE transport Using LP From line 66 ---- cost =E=...
- 7 years ago
- Forum: Solvers
- Topic: Multiobjective optimization
- Replies: 1
- Views: 4550
Re: Multiobjective optimization
Your analysis is correct. For other readers, this is only for the GAMS/Gurobi solver. Anyhow, in case of "MultiObj=1" the coefficients in the master objective "just" help to build the different priority classes. When I implemented this, I had in mind that I wanted to go easily fr...
- 7 years ago
- Forum: Solvers
- Topic: Problems with the initial point
- Replies: 4
- Views: 6564
Re: Problems with the initial point
Tiago, I agree that we should make sys12 more visible and give it a better name, but I also believe that this is a good default. Even global solvers benefit from a good starting point because they use local solvers for local search (e.g. BARON does a multi-start based on the initial point that hopef...
- 7 years ago
- Forum: Solvers
- Topic: CPLEX LP Warmstart
- Replies: 3
- Views: 6103
Re: CPLEX LP Warmstart
It does not matter where the basis (complete or incomplete) comes from. You just need to set (.l and) .m of your variables and equations. I did not get the experiment you tried to do in your attached GAMS model. To me it looks like that the second solve successfully restarted from a basis.
-Michael
-Michael
- 7 years ago
- Forum: Solvers
- Topic: CPLEX stuck "Removing shift" on MILP
- Replies: 3
- Views: 5201
Re: CPLEX stuck "Removing shift" on MILP
This truly looks like a Cplex bug or numerical issue. If you add options writesav prob.sav writeparam param.prm to your GAMS/Cplex option file you could submit these two files together with the entire log to support@gams.com or directly to the Cplex folks. Please also provide information about the p...
- 7 years ago
- Forum: Solvers
- Topic: Problems with the initial point
- Replies: 4
- Views: 6564
Re: Problems with the initial point
Local NLP solvers need a good starting point to improve on. The starting point you provide (0,0) can't be evaluated and hence the solver could not compute a direction that improves the situation. Hence GAMS checks if the starting point can be calculated. If not, GAMS will not pass the model to the s...
- 7 years ago
- Forum: Bugs
- Topic: Gams does not print solution when click "Interrupt" on windows 10
- Replies: 1
- Views: 8284
Re: Gams does not print solution when click "Interrupt" on windows 10
The problem is that GAMS waits for the user to react on the "Terminate batch job (Y/N)?". With older OS versions this was not a problem but it surfaced eventually. Anyhow, a newer GAMS version (>=24.0) fixes this problem (see http://www.gams.com/latest/docs/releasenotes/24.0.html#gams). Yo...
- 7 years ago
- Forum: Solvers
- Topic: CPLEX LP Warmstart
- Replies: 3
- Views: 6103
Re: CPLEX LP Warmstart
Leo,
The key GAMS/Cplex option for LP restarts is 'advind' (http://www.gams.com/latest/docs/solvers ... PLEXadvind). Perhaps you can post some logs or even share your model and starting point, so we have more to go on.
-Michael
The key GAMS/Cplex option for LP restarts is 'advind' (http://www.gams.com/latest/docs/solvers ... PLEXadvind). Perhaps you can post some logs or even share your model and starting point, so we have more to go on.
-Michael